Display colorsync profile remains unapplied?

[Chris Murphy]

On Mar 20, 2007, at 7:16 PM, Christopher Hunt wrote:

> Hi there,
>
> I have a remote CPU that is driving two projectors. Each projector  
> is connected via DVI and they are in a mirror configuration. Both  
> projectors have been assigned a Generic RGB profile given that the  
> colours generally look brighter than as per the projector's  
> Colorsync profile. However... one projector remains brighter than  
> the other and it looks as though the Generic RGB Colorsync profile  
> has been applied to it but not the other.

Depending on the machine you're using and OS version, it may look  
like you can separately set different profiles to two displays but in  
reality you can't. So one of them might not be used.

But it's more likely the two displays behave differently. Are they  
connected to the same video card, or two different cards?

> I'll also add that the brighter display is not just brighter, but  
> the blues are richer etc. so there does appear to be colour  
> differences. It may well be that the differences are associated  
> with a newer bulb in the brighter projector but when I saw it  
> yesterday it did look like a Colorsync difference.

Well chances are it isn't a ColorSync difference, because most  
applications are stupid when it comes to color management. Most  
applications simply use the display profile as the source profile and  
then Quartz uses the display profile as destination. When source =  
destination, there is no transformation, so ColorSync isn't even  
doing anything. That would mean the displays are just different. But  
to know for sure, we'd need more information. Machine, video cards,  
OS version, what application (and if it's obscure does it tell the OS  
what the source color space is correctly or not), etc.


Chris Murphy
Color Remedies (TM)
New York, NY
----------------------------------------------------------------------
Co-author "Real World Color Management, 2nd Ed"